1. Field of the Invention
The present invention concerns a method and device for the automatic allocation of addresses to a plurality of modules interconnected by a communication network with an arborescent topology.
It applies in particular, but not exclusively, to a plurality of modules interconnected by an electric distribution network used both for the electric feeding of the modules and as a communication network for the transmission of digital messages between modules via a modulated carrier current.
It is applicable in particular to the remote control and monitoring of urban lamp posts.
2. Description of the Prior Art
It has been observed that an electric distribution network generally has a complex topology comprising a large number of intersections distributed randomly. In addition, the knowledge of the exact topology of the network has quite often disappeared, said network generally resulting from operations of successive installations carried out over several tens of years.
Moreover, if it is desired to be able to communicate with each module separately, it is necessary to allocate one address to each module.
In the context of a network of this types the allocation of an address to each module poses a large number of problems.
In fact, it is first of all necessary to ensure that the method for addressing the various modules with which it is desired to communicate is able to be applied to any network topology. Next, if it is desired to interconnect a large number of modules, the addressing of the various modules must be able to be carried out with fastidious handlings which might result in significant risks of error.
It is also essential to be able to easily add a module in the network without requiring manual interventions on other modules.
Furthermore, the range of transmissions by carrier current is relatively small. Thus, it is necessary to repeat the transmitted messages so that they arrive at their destination. Thus, it is essential that the address of each module contains the path by which the message needs to be transited so that it arrives at its destination and so as to be able to determine if a message in a specific path needs to be repeated.
The method described in the patent FR 2 734 111 filed by the Applicant is able to partially resolve these problems to the extent where it is necessary to act manually on each module still not having any address and on the module already having an address situated immediately upstream with respect to a central unit situated at the root of the arborescent network, the address of the module with no address being determined according to the address of the upstream module already having an address and according to the number of modules already having an address and connected directly to the module with an address and situated downstream of the latter.
Thus, this method does have the drawback of requiring the intervention of operators on the terrain concerned, said operators needing to take action on the control buttons provided on each module. In addition, these modules can be only accessed with difficulty as for example they may be installed several meters from the ground at the top of urban lamp posts. Furthermore, this method is not able to fully eliminate any risk of error as it is possible to initiate the allocation of an address of a module not immediately situated downstream of a module having an address.